yuzu/src/shader_recompiler/frontend/ir/basic_block.h

// Copyright 2021 yuzu Emulator Project
// Licensed under GPLv2 or any later version
// Refer to the license.txt file included.

#pragma once

#include <initializer_list>
#include <map>
#include <span>
#include <vector>

#include <boost/intrusive/list.hpp>

#include "common/bit_cast.h"
#include "shader_recompiler/frontend/ir/condition.h"
#include "shader_recompiler/frontend/ir/value.h"
#include "shader_recompiler/object_pool.h"

namespace Shader::IR {

class Block {
public:
    using InstructionList = boost::intrusive::list<Inst>;
    using size_type = InstructionList::size_type;
    using iterator = InstructionList::iterator;
    using const_iterator = InstructionList::const_iterator;
    using reverse_iterator = InstructionList::reverse_iterator;
    using const_reverse_iterator = InstructionList::const_reverse_iterator;

    explicit Block(ObjectPool<Inst>& inst_pool_, u32 begin, u32 end);
    explicit Block(ObjectPool<Inst>& inst_pool_);
    ~Block();

    Block(const Block&) = delete;
    Block& operator=(const Block&) = delete;

    Block(Block&&) = default;
    Block& operator=(Block&&) = default;

    /// Appends a new instruction to the end of this basic block.
    void AppendNewInst(Opcode op, std::initializer_list<Value> args);

    /// Prepends a new instruction to this basic block before the insertion point.
    iterator PrependNewInst(iterator insertion_point, Opcode op,
                            std::initializer_list<Value> args = {}, u32 flags = 0);

    /// Set the branches to jump to when all instructions have executed.
    void SetBranches(Condition cond, Block* branch_true, Block* branch_false);
    /// Set the branch to unconditionally jump to when all instructions have executed.
    void SetBranch(Block* branch);
    /// Mark the block as a return block.
    void SetReturn();

    /// Returns true when the block does not implement any guest instructions directly.
    [[nodiscard]] bool IsVirtual() const noexcept;
    /// Gets the starting location of this basic block.
    [[nodiscard]] u32 LocationBegin() const noexcept;
    /// Gets the end location for this basic block.
    [[nodiscard]] u32 LocationEnd() const noexcept;

    /// Adds a new immediate predecessor to this basic block.
    void AddImmediatePredecessor(Block* block);

    /// Gets a mutable reference to the instruction list for this basic block.
    [[nodiscard]] InstructionList& Instructions() noexcept {
        return instructions;
    }
    /// Gets an immutable reference to the instruction list for this basic block.
    [[nodiscard]] const InstructionList& Instructions() const noexcept {
        return instructions;
    }

    /// Gets an immutable span to the immediate predecessors.
    [[nodiscard]] std::span<Block* const> ImmediatePredecessors() const noexcept {
        return imm_predecessors;
    }

    /// Intrusively store the host definition of this instruction.
    template <typename DefinitionType>
    void SetDefinition(DefinitionType def) {
        definition = Common::BitCast<u32>(def);
    }

    /// Return the intrusively stored host definition of this instruction.
    template <typename DefinitionType>
    [[nodiscard]] DefinitionType Definition() const noexcept {
        return Common::BitCast<DefinitionType>(definition);
    }

    [[nodiscard]] Condition BranchCondition() const noexcept {
        return branch_cond;
    }
    [[nodiscard]] bool IsTerminationBlock() const noexcept {
        return !branch_true && !branch_false;
    }
    [[nodiscard]] Block* TrueBranch() const noexcept {
        return branch_true;
    }
    [[nodiscard]] Block* FalseBranch() const noexcept {
        return branch_false;
    }

    void SetSsaRegValue(IR::Reg reg, const Value& value) noexcept {
        ssa_reg_values[RegIndex(reg)] = value;
    }
    const Value& SsaRegValue(IR::Reg reg) const noexcept {
        return ssa_reg_values[RegIndex(reg)];
    }

    [[nodiscard]] bool empty() const {
        return instructions.empty();
    }
    [[nodiscard]] size_type size() const {
        return instructions.size();
    }

    [[nodiscard]] Inst& front() {
        return instructions.front();
    }
    [[nodiscard]] const Inst& front() const {
        return instructions.front();
    }

    [[nodiscard]] Inst& back() {
        return instructions.back();
    }
    [[nodiscard]] const Inst& back() const {
        return instructions.back();
    }

    [[nodiscard]] iterator begin() {
        return instructions.begin();
    }
    [[nodiscard]] const_iterator begin() const {
        return instructions.begin();
    }
    [[nodiscard]] iterator end() {
        return instructions.end();
    }
    [[nodiscard]] const_iterator end() const {
        return instructions.end();
    }

    [[nodiscard]] reverse_iterator rbegin() {
        return instructions.rbegin();
    }
    [[nodiscard]] const_reverse_iterator rbegin() const {
        return instructions.rbegin();
    }
    [[nodiscard]] reverse_iterator rend() {
        return instructions.rend();
    }
    [[nodiscard]] const_reverse_iterator rend() const {
        return instructions.rend();
    }

    [[nodiscard]] const_iterator cbegin() const {
        return instructions.cbegin();
    }
    [[nodiscard]] const_iterator cend() const {
        return instructions.cend();
    }

    [[nodiscard]] const_reverse_iterator crbegin() const {
        return instructions.crbegin();
    }
    [[nodiscard]] const_reverse_iterator crend() const {
        return instructions.crend();
    }

private:
    /// Memory pool for instruction list
    ObjectPool<Inst>* inst_pool;
    /// Starting location of this block
    u32 location_begin;
    /// End location of this block
    u32 location_end;

    /// List of instructions in this block
    InstructionList instructions;

    /// Condition to choose the branch to take
    Condition branch_cond{true};
    /// Block to jump into when the branch condition evaluates as true
    Block* branch_true{nullptr};
    /// Block to jump into when the branch condition evaluates as false
    Block* branch_false{nullptr};
    /// Block immediate predecessors
    std::vector<Block*> imm_predecessors;

    /// Intrusively store the value of a register in the block.
    std::array<Value, NUM_REGS> ssa_reg_values;

    /// Intrusively stored host definition of this block.
    u32 definition{};
};

using BlockList = std::vector<Block*>;

[[nodiscard]] std::string DumpBlock(const Block& block);

[[nodiscard]] std::string DumpBlock(const Block& block,
                                    const std::map<const Block*, size_t>& block_to_index,
                                    std::map<const Inst*, size_t>& inst_to_index,
                                    size_t& inst_index);

} // namespace Shader::IR